From e865f69b4e4aa440cc8efaac4f9972bc309f4a15 Mon Sep 17 00:00:00 2001
From: Steve Baker <sbaker@redhat.com>
Date: Mon, 30 Apr 2018 17:26:58 +1200
Subject: [PATCH] Basic template based Dockerfile approach

---
 tasks/main.yml          | 22 +++++++++++++++++++++-
 templates/Dockerfile.j2 |  2 ++
 vars/main.yml           | 14 ++++----------
 3 files changed, 27 insertions(+), 11 deletions(-)
 create mode 100644 templates/Dockerfile.j2

diff --git a/tasks/main.yml b/tasks/main.yml
index ed97d53..4754fec 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -1 +1,21 @@
----
+- name: Set default modified_append_tag
+  set_fact:
+    modified_append_tag: "{{ lookup('pipe','date +-modified-%Y%m%d%H%M%S') }}"
+  when: modified_append_tag is undefined or modified_append_tag == None
+
+- name: Create image build context directory
+  tempfile:
+    state: directory
+    prefix: tripleo-modify-image
+  register: context_dir
+
+- name: Write Dockerfile to {{ context_dir.path }}
+  template:
+    src: Dockerfile.j2
+    dest: "{{ context_dir.path }}/Dockerfile"
+
+- name: Modify image  
+  docker_image:
+    name: "{{ modified_image }}{{ modified_append_tag }}"
+    path: "{{ context_dir.path }}"
+
diff --git a/templates/Dockerfile.j2 b/templates/Dockerfile.j2
new file mode 100644
index 0000000..97ded3f
--- /dev/null
+++ b/templates/Dockerfile.j2
@@ -0,0 +1,2 @@
+FROM {{ source_image }}
+LABEL modified_append_tag={{ modified_append_tag }}
diff --git a/vars/main.yml b/vars/main.yml
index 8290715..4fc97a4 100644
--- a/vars/main.yml
+++ b/vars/main.yml
@@ -2,19 +2,13 @@
 # Mandatory fully qualified reference to the source image to be modified
 source_image:
 
-# Mandatory path to the directory containing the Dockerfile to modify the image
-modify_dir_path:
-
 # String to be appended after the tag to indicate this is a modified version of
-# the source image.
-modified_append_tag: "-modified-{{lookup('pipe','date +%Y%m%d%H%M%S')}}"
+# the source image. Defaults to the output of the command
+# "date +-modified-%Y%m%d%H%M%S"
+modified_append_tag:
 
 # If set, the modified image will be tagged with this reference. If the purpose
 # of the image is not changing, it may be enough to rely on modified_append_tag
 # to identify that this is a modified version of the source image.
 # modified_append_tag will still be appended to this reference.
-modified_image:
-
-# Build-time variables for the image build. The role variables source_image and
-# modified_append_tag will be merged with this dict.
-modify_buildargs: {}
+modified_image: {{ source_image }}